This invention relates to tubular graft structures for replacing or supplementing a patient""s natural body organ tubing. More particularly, the invention relates to structures for connecting the ends of such tubular graft structures to body organ tubing.
A patient""s weakened or diseased body organ tubing can often be repaired by replacing or supplementing the patient""s existing natural body organ tubing with an artificial graft structure. One suitable type of artificial graft structure uses a tubular nitinol mesh frame covered with a silicone coating, as described in Goldsteen et al. U.S. Pat. No. 5,976,178. Such grafts are highly flexible, so they recover their shape after being stretched. Accordingly, a graft of this type may be stretched axially to reduce its radial dimension and then installed in a patient intraluminally (e.g., through an existing vein or artery). Once delivered to the proper location within the patient, the axially stretched graft may be released, whereupon it expands to regain its original shape.
In addition, flexible artificial grafts may be made distensible like natural body organ tubing to help reduce clot formation when used in vascular applications. Flexible artificial grafts may also be made biocompatible by adjusting their porosity and the composition of their coatings.
Various connector structures may be used to attach flexible artificial grafts to a patient""s body organ tubing. For example, a graft may be surgically attached to a patient""s body organ tubing with sutures. To install a graft intraluminally, a pronged ring may be expanded from within the end of the graft, thereby piercing the graft and attaching it to surrounding body organ tubing. Barbed flaps and wire hooks may also be used to attach grafts to body organ tubing. Connector structures of these types and other suitable connector structures are described in the above-mentioned Goldsteen et al. U.S. Pat. No. 5,976,178 and in Bachinski et al. U.S. Pat. No. 6,036,702.
Although connector structures of these types have various useful features, it would be desirable if connector structures with other features were available.
It is therefore an object of the present invention to provide improved connector structures for attaching grafts to a patient""s body organ tubing.
This and other objects of the invention are accomplished in accordance with the principles of the present invention by providing connectors for attaching flexible graft structures to body organ tubing. The connectors may be entirely or nearly entirely from wire. The flexibility of the wire allows the connectors to be radially contracted during intraluminal insertion into a patient and subsequently radially expanded at the installation site. In addition, the flexibility of the structures makes it possible to match the compliance or flexibility characteristics of the connector with the compliance of the body organ tubing and artificial graft structures at the attachment site.
To form a secure connection between the graft and the body organ tubing, the wire for the connectors can be arranged in two opposing groups of wires near the end of the graft. The wires in the first of the two groups are arranged about the periphery of the end of the graft. The wires in the second group are spaced by a gap from the wires in the first group along the longitudinal axis of the graft. The body organ tubing is held in the gap by the two opposing groups of wires.
The wires in the connectors may be loops or may be individual wires. The wires may also be curved to accommodate connections between grafts and natural body organ tubing that is tubular in shape.
If desired, the connectors may be used to form non-right-angle connections between grafts and body organ tubing.
The connectors may also be annular in shape. Such annular connectors may be formed by molding a heat-sensitive wire mesh over an appropriate mandrel and heat treating the wire.
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.